Hi, This is Marco Quaglia,
The best/fastest IMAQ Grab you can do is the asyncronous technics, I mean run the Init, buffer allocation, trig config and stat out of the loop and inside the loop run just the Get/Extract/Copy functions.
To do this you have to use the LowLevel functions.
Moreover, using the above function you can build a Seuqnece or Ring acquisition allocating more that one buffer.
Try it !
Ciao